KR930008403B1 - Reinforcing material - Google Patents

Abstract

The invention relates to a reinforcing material for duroplastics and a process of preparing the same by embedding hollow body fillers (microspheres) in the interspaces of the fibers of a web, knitted fabric or stitch bonded products of fibers having a high modulus of elasticity. By virtue of the incorporation of the hollow body fillers, the particle diameter of which amounts to between 20 and 300 mu m, the absorbing capacity for liquid curable resins can be adjusted to the desired value. The process of the subject invention teaches to incorporate the unexpanded preform of a hollow body filler into the interspaces of the fibers and to subject the so-obtained material for a sufficient period of time to the temperature necessary for the blowing process of the preform. The reinforcing material can be used for preparing light laminates of duroplastic materials (FIG. 1).

Description

Reinforcement

1 is a plan view of a material; Perspective view.

2 is a side cross-sectional view of a material.

The present invention relates to a reinforcing material of durro plastic and a method for manufacturing the same.

There has been a constant effort in manufacturing plastic molded articles to reduce weight without mechanically degrading strength in terms of design and economy.

By reinforcing the reinforcement plastics with fibers, a so-called fiber composite is obtained which is characterized by substantial high modulus, i. In particular, fiber composites made from duroplastics, such as classic anino- and phenoplastic resins, epoxide resins (EP resins), polyester- (UP resins) and other reactive resins, have been found in a variety of areas and for a variety of purposes, in particular cured moldings and molding laminates. Widely used for material, mold resin or surface protection.

Glass fiber reinforced with epoxide or polyester resin is one of the most widely used fiber composites. Molded articles made of this material are prepared by moistening the glass fibers in liquid Duro-Plastic resin and putting them in a mold. Hardening is performed by the catalyst added to liquid synthetic resin. Plastic reinforced glass fibers are molded without pressure or by various low pressure methods and processed to form desirable large molded articles characterized by low weight and unusual improvements in service life such as hulls, automotive parts, storage containers, pipes. The use and strength characteristics of this type of material, on the one hand, the greater the quality and weight ratio of the reinforcing fibers, the better the strength data.

The no-pressure method is used to produce a series of small molded articles requiring large molded articles and expensive molding apparatus that cannot be maintained in cost.

One non-pressure method is manual lamination (hand stacking), which consists of stratifying layers of flat products such as mats, fabrics, zip fabrics, etc. wetted with liquid resin until a desired thickness of the material is obtained. .

The winding method is also a non-pressure method which consists of winding up a resin-wetting reinforced fabric or fiber strand mandrel or cylindrical member and curing it. In the stretching process, the reinforcing fabric or fiber strands are wetted with a resin and then stretched through forming dies.

The ratio of reinforcing fibers to the total weight of the fiber composite, which is critical to the strength properties, can only be affected within limits in the non-pressure method. When the reinforcing fibers are immersed in the liquid resin, the existing cavities between the unit filaments are filled with the resin depending on the absorbency of the fibers.

Thus, the less the ratio of reinforcing fibers in the total weight, the greater the absorbency of the reinforcing fibers based on volume. Glass fibers available on the market as reinforcements of fiber composites have the quality of conventional standards with limited resin absorbency allowing manufacturers to calculate specific weights and gross weight of molded articles.

For example, a fiberglass mat composed of chopped or elongated filaments has a resin pickup (adhesion amount) of about 70 to 75% by weight, and the absorbency of the glass fiber fabric consisting of intertwined yarns and rovings is about 65 to Up to 70%. The resin pick-up is still about 60-65% in the stitch (suture) joints where yarns, dimers and rovings are not woven together and are confined at intersections and connected to each other.

Thus, specific gravity of about 1.5 to 1.7 is obtained in laminates made from fiberglass mats, and specific gravity of woven and stitched joints is about 1.7 to 1.9. In order to reduce the weight of the plastic molded article without weakening the mechanical strength, the resin may be partially substituted with a filler having a specific gravity less than the immersion resin while maintaining a constant proportion of the reinforcing fibers.

Light fillers, so-called hollow fillers, so-called "microspheres", are therefore suitable for being capable of organic and inorganic properties.

Hollow microglass spheres are light fillers that exhibit the small specific gravity required to reduce density. A type of hollow microsphere is also composed of polymerized organics, for example the use of the trade name Expanshell® with a thermoplastic shell made of vinylidene chloride-acrylonitrile-copolymer. The particle size ranges from 50 to 300 μm and the density is about 20 to 40 kg / m 3.

Preformed unexpanded formations of hollow fillers, such as copolymers of polyvinyl chloride or vinylidene with swelling agents such as isobutane, are also standard in the market. Unexpanded particles (eg, “unexpanded” xpanshell) have a particle size of 5-10 μm. In order to swell it, it is placed at a temperature of about 80 to 150 ° C. corresponding to the softening point of the microspheres. As soon as the softening point is reached, the entrained propellant expands the individual filling particles into the hollow sphere by evaporation.

Due to the low weight of the hollow filler, attempts have been made to mix it with the laminate resin and incorporate it into the fiber composite for weight reduction. However, when using this method, the viscosity and lamination activity of the immersion resin are adversely affected, and incorporation of relatively coarse granular hollow fillers into the cavity of the reinforcing fibers was unsuccessful, but was retained on the surface. Another difficulty is that weak hollow fillers can no longer contribute to the intended weight loss because they do not withstand any large mechanical loads and are already partially destroyed upon stirring in the laminate or during the actual lamination process.

It is well known that unexpanded microspheres having a latex of a curing binder are sprayed onto a fabric of textile staple fibers (artificial fibers), and the web thus obtained is heated to the softening point of the thermoplastic microspheres. In such a way, a product having a large volume of non-absorbent water having a high absorbency of water is obtained, which can be used as a surgical outer coat and dust mop or wiping cloth (US-A-3676288). Such bonded fiber fabrics have also been used in the manufacture of fiber-reinforced plastics formed by the penetration of liquid resin-cured mixtures. However, here it is only suitable as a base material because of its low strength, but the Duroplastic reinforcement of continuous filaments with a higher modulus than hardened Duroplastics must be done (DE-B-24 33 427).

The present invention is based on the problem of producing a processing reinforcement for a processor which avoids the above-mentioned disadvantages of incorporating a used body filler into the fiber composite and reduces the specific gravity of the fiber composite without compromising strength.

Continuous parallel basic filaments in roving, yarn or dimer yarns with high modulus of elasticity are drooped or separated using pre-formed, water-soluble binder-glass suspensions of preformed unexpanded particles of hollow plastic microspheres, as a result of which the resulting space is mainly filled with particles The material thus obtained is placed at the required temperature for the expansion process of the preformed particles for the required time, and is made from roving, yarn or loose spun yarn or web knitted fabric or fabric without compromising the strength of the composite made from such durroplastic. It has now been surprisingly found that it is also possible to permanently reduce the specific weight of conventional reinforcements for resin pickups and durplastics in the form of one stitched joint.

When we talk about continuous filaments or fibers, we mean not only at least a few centimeters in length of textile fibers or staple fibers, but also roving, yarn, or loose spinning joints that are commonly used for reinforcement purposes, or appear on the market. It is a very large length of textile fibers or staple fibers found in webs, knitted fabrics or stitched joints made therefrom.

As a result of the manufacturing process, basic filaments such as filaments, parallel rovings, continuous yarns, etc., are commonly used to prepare rather adhesive garments. Continuous strands were treated with a soluble suspension of unexpanded microspheres in accordance with the present invention to dissolve and remove the water soluble garment or binder in water. Only in this way can it be possible to separate the basic filaments from one another and at least increase them so that the pre-generated unexpanded particles of the hollow microspheres can penetrate the resulting space and fill it a lot.

Therefore, it is preferable that the separation of the basic filament and the introduction of the unexpanded microspheres are performed simultaneously with treating the continuous strand with the demand suspension. However, it is also possible to remove clothing or binders attached to rovings, yarns or dimers during separation before introducing the hollow microspheres. If a garment or adhesive is not sufficiently soluble in water, a solvent may be used for that purpose.

Separation of the basic filaments and / or introduction of unexpanded hollow microspheres into the fiber strands allows for intrinsic penetration of filler particles such that the fiber strands are intensely pooled in a bath consisting of a water-soluble binder-glass bath while the parallel basic filaments of the reinforcing fibers are unfolded. (fooling) can be done in a manner that is placed in the process. The fiber strands may be placed in water or suspension, for example, under high pressure jets of 2 to 10 bar, in order for the basic filaments to move preferably with each other and to insert unexpanded microspheres therebetween. The same method can be used to process stitched joints made from webs, knitted fabrics or continuous fibers. Following particle introduction, the fiber strands or fabrics are stripped with suitable means such as lips or eyelets, resulting in unexpanded hollow microspheres remaining unattached to the surface.

Fiber strands or webs treated in such a way are drawn through a drying tuner and dried with air and heat. Because the strands are pressurized and the base filaments squeeze in the microspheres sandwiched between them, the microspheres sandwiched between loose and dried fiber strands are loose spun yarns with roving, yarn or parallel continuous basic filaments despite the lack of any binder. Can not fall from.

After drying the fiber strands or webs are drawn through the oven at a temperature of 80 to 150 ° C. and the time it is exposed to heat is from 15 seconds to about 15 minutes. Due to the exposure of heat, the propellant expands the microspheres to a diameter of about 20 to 300 μm, and the expanded hollow microspheres compress the basic filaments of the fiber strands and substantially fill the entire space, whereby the diameter of the fiber strands or flat products made therefrom The thickness of can be increased by 2 to 30 times. The expansion process is carried out in such a way that the microspheres towards the distal end have some relation to the basic filament at the same time.

By means of the process of the present invention, reinforcing materials suitable for duroplastics are obtained by containing hollow fillers having a particle size of 20 to 300 μm, which can be disposed of directly into the mold in this form. The resin pickup depends on the amount of filler particles added and the temperature treatment strength and can be continuously adjusted to the point where pickup is no longer possible. Glass fibers widely used for cost reasons are questioned as suitable fibrous materials for the production of the Duroplastic reinforcement of the present invention, but modification of the reinforcement is possible by using other fibers having a high modulus such as carbon fibers and aramid fibers. Reinforcing fibers in the form of woven or nonwoven mats have been found to be particularly suitable for adaptation with hollow fillers.

The stitch joints described above are produced in limited lengths, such as products having a width of about 100 cm by cutting rovings, yarns or loose spun yarns with the help of special machines such as "malimo" stitch joints from continuous fibers. It is done. This length is then connected to the knitted filament like a crossbar on a rope ladder to obtain a flat product.

In this case the fiber strands can be connected with the fiber strands that are loosened in the transverse direction rather than in the longitudinal direction, whereby the strands intersect each other at the intersection.

Another possibility of connecting continuous fiber strands to products in flat products is to interweave. The structure of the web is crucial to the structure of the finished product. The fiber strands into which the microspheres are to be inserted in a preferred manner according to the process described above are very loose with warp or weft. If the flat finished product is to be inflated, a characteristic structure is caused because the balloon-like expansion of the fiber strand occurs essentially between the intersections of the warp and weft yarns during tie up at the intersection. Stitch joints or webs are shaped like pearl chains that are joined together. This material has excellent properties in some areas of use because of its unusual structure. For example, if several layers of such a flat product are placed in the interlocking portion of each layer, a high cross-lamination force occurs in the laminated material. Again, the channel formed as a result of the tieup has a desirable effect. The use of this material in a press process or vacuum injection ensures excellent fluidity and a constant distribution of liquid resin in the mold.

Very solid webs, i.e. webs with high filaments of warp and weft, only slightly change the thickness of the material by the blowing process. If the Duroplastic Molders require the highest strength laminate material at the cost side, the resin part should be as small as possible and the reinforcing fiber part of the total volume of the laminate should be as large as possible, which is a strong and strong web to the extent that the material thickness can no longer be increased. This can be done by selecting a structure. Strong expansion of the web during the blowing process can be prevented, for example, by blowing between the range spacers so that the sphere can only fill the space between the basic filaments. From the quality of the kind, for example, the entire structure of the laminate, which is preferably used in the manufacturing process of the present invention, can be provided without the additional use of the sheath layer. In contrast, if the molder requires a very light and bulky material, for example for processing in a laminate core, the thickness of the raw material is increased 2 to 30 times, in particular 5 to 10 times, with the choice of loose and coarse fabrics. Can be.

In other words, the hollow filler was inserted, the resin pick-up of the reinforcing fiber was simultaneously reduced and the thickness of the material was increased with respect to the starting material. Materials obtained with high expansion, which are made extremely light and have a reservoir pick-up, are preferred for laminates, for example, having a fixed star resistance to bending. The described embodiment of the present invention for modifying yarns, dimers and rovings with unexpanded hollow fillers to obtain preformed flat products is a finished product having a wide range of applications depending on whether the web produced therefrom has a loose and robust structure. Access to There are a variety of methods for making reinforcement with reservoir pickup and flattened reduced specific weight. Obtained rovings, yarns or dimers with embedded hollow microspheres can be woven into a web, knitted fabric or stitched joint in a similar manner.

As already described above, it is possible to separate continuous basic filaments and introduce preformed unexpanded hollow plastic microspheres with a stitch joint of web, knitted fabric and continuous fibers, which are exposed to an expansion process or are still unexpanded before expansion process. A web, knitted fabric or stitched joint can be made from roving, yarn or dimer yarn with one microsphere embedded particle.

It is also an object of the present invention that the parallel basic filaments are stretched apart or separated, and the cavities between the basic filaments are remarkably filled with hollow plastic microspheres and resin pickups having a diameter of 20 to 300 μm and are in the form of spun dimers or yarns, rovings. It relates to a reinforcing agent for furnace uroplastic.

In the case of the strand type as well as the flat reinforcing agent of the present invention, the hollow microspheres are preferably inserted in an amount of 2 to 30 times the thickness of the starting material, particularly 5 to 10 times.

The reinforcing agent of the present invention is preferably used for the production of light laminates made of durroplastic. It is therefore an object of the present invention to contain reinforcing agents which are substantially stretched apart or moved apart and are remarkably filled with hollow plastic microspheres having a diameter of 20 to 300 μm in the hollow spaces between the basic filaments and having roving, yarn or high modulus of elasticity. And a low specific weight characterized by a loose spun dimer of continuous basic filaments arranged in parallel.

In the drawings, the reinforcing material of the Duro-Plastic reinforcement of the present invention is drawn in an electron microscope with a magnification of 2.5 cm in 1 degree and 2 degrees in accordance with about 100 μm.

1 degree top view material; Perspective view is shown.

The microspheres 2 of the expanded thermoplastic material (thermoplastic microspheres) inserted between the individual glass fibers can be clearly seen, and the microspheres are heated for a short time and the vinylidene chloride-acrylonitrile copolymer (unexpanded Expancel ^R ) Is prepared from unexpanded particles. The remaining cavity filled with immersion resin is marked with 3.

Example 1

Parallel rovings with 12240 continuous base glass fibers are drawn through a bath consisting of an aqueous suspension containing 10% by weight of unexpanded Expancel by unscrewing a 10000m feed coil at a rate of 2m / min. In the bath the strands are subjected to ultraviolet vibrations with a conventional commercial generator. Externally placed adhesive particles and excess were stripped through the eyelets sized for that purpose. Parallel roving treated in such a manner occupies 8% by weight of particles and is drawn through a dry tunnel introduced with hot air at a temperature of 80 ° C.

The fiber strands are then drawn through an oven heated with infrared radiation at 150 ° C. It left about 3 minutes in the oven. The hollow microspheres had an average diameter of 60 µm and the fiber strands increased 10 times the diameter.

Example 2

A glass fiber web of flax cloth having a warp of 60 tex and 15 fibers / cm and a weft of 136 tex and 3 fibers / cm was stretched through the bath in the same manner as in Example 1 and knocked down with a rubber roll. Excess water and unexpanded microspheres attached to the surface were stripped as the material passed through the rubber lip. The material contained 25 g / m 2 of unexpanded filler. It was then dried in a hot-air oven and heated in a hot-air oven by infrared irradiation for 3 minutes to bring the final temperature to 150 ° C.

The thickness of the web increased 10 times due to expansion of the hollow microspheres and the average size of the hollow microspheres was 60 μm. Some layers of this web were optionally placed in molds with conventional commercial unsaturated polyester resins. The use of the resin showed that the density of the nebulizer and the optical fiber composite was 0.7 g / cm 3. Resin pick-up was about 35% by volume.

Claims (20)

A substantial part of the parallel base filament without any bonding agent is stretched or separated and is mainly filled with hollow plastic microspheres with a diameter of 20 to 300 μm of space between the base filaments, with resin pickup and reduced specific gravity. A stiffener of duroh plastic in the form of loose spun yarn, yarn or roving of parallel arrayed continuous basic filaments having a high modulus of elasticity. The reinforcing material according to claim 1, wherein the hollow microspheres are inserted in an amount such that the thickness of the manufactured non-bonded roving, yarn or loose spun yarn is 2 to 30 times, in particular 5 to 10 times, the thickness of the starting material. Substantial portions of parallel base filaments without any bonding agent are stretched apart or separated, and the space between the base filaments is mainly filled with hollow plastic microspheres having a diameter of 20 to 300 μm, characterized by reduced resin pickup and specific gravity. A stiffener of duroh plastic, which is in the form of a loose spun fused yarn, a web of yarn or roving, a knitted fabric or a stitchy joint having a continuous parallel-arranged basic filament having a high modulus of elasticity. 4. The reinforcement as claimed in claim 3, wherein the hollow microspheres are inserted in an amount such that the thickness of the prepared non-bonded web, knitted fabric or stitched joint is 2 to 30 times the thickness of the starting material, in particular 5 to 10 times. The reinforcing material according to claim 1, wherein the fiber having a high modulus is made of glass, carbon or aramid fiber. 2. The reinforcing material according to claim 1, wherein the true filler has a true density of 0.02 to 0.2 kg / dm 3. 2. The reinforcement as claimed in claim 1, wherein the absorbency of the liquid curable resin, in particular epoxy resin or unsaturated polyester resin, is adjusted to the required value by the amount of the hollow filler inserted. The reinforcing material according to claim 1, wherein the hollow microspheres are made of thermoplastic. Continuous parallel-arranged basic filaments with high modulus in roving, yarn, or loose spun yarn are laid down or moved apart using a water-soluble binder-glass suspension of preformed unexpanded particles of hollow plastic microspheres, resulting in The cavity is mostly filled with particles having a particle size of 5 to 10 µm, and the material thus obtained is placed at a temperature necessary for the expansion process of the previously formed particles for a required time period. 10. The method of claim 9, wherein the roving, yarn, or dimer with embedded hollow microspheres is processed into a web, knitted fabric, or stitched joint. 10. A method according to claim 9, characterized by treating roving, yarn or loose spun yarn already present in the form of a web, knitted fabric or stitched joint. 10. A method according to claim 9, wherein the roving, yarn or dimer with hollow microspheres inserted preformed unexpanded particles is made of a web, knitted fabric or stitched joint prior to the expansion process. 10. A method according to claim 9, wherein the product is subjected to a pooling process in a bath consisting of water-soluble conjugated-glass suspension of particles in order to incorporate unexpanded particles into yarns, dimers or rovings or flat fabrics made therefrom. . 10. The method according to claim 9, wherein the amount of preformed unexpanded particles of the hollow filler is adjusted in such a way that the thickness of the starting material is increased by 2 to 30 times, in particular the expansion of the preformed hollow microspheres by 5 to 10 times later. How to feature. 10. The method of claim 9, wherein the high modulus fibers consist of glass, carbon or aramid fibers. 10. The process according to claim 9, wherein the absorbent force of the liquid curable resin, in particular epoxy resin or unsaturated polyester resin, is adjusted to the required value by the amount of the hollow hollow body inserted. 10. The method of claim 9, wherein the temperature of the expansion process is between 80 ° C and 150 ° C. 10. The method of claim 9, wherein the process is performed between range spacers in an expansion process. The reinforcement according to claim 1 is used to make light durroplastic laminates. Roving, yarn or loose spuns of parallel-arranged continuous basic filaments with high modulus, containing reinforcement filled with hollow plastic microspheres of 20 to 300 μm in diameter, with substantial portions of the hollow or interspaced apart filaments apart. A low specific gravity fluoroplastic fiber composite, which is a plywood.

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